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Welcome everyone to Wednesday Nite @ the Lab. I'm Tom Zinnen, I work here at the UW-Madison Biotechnology Center. I also work for UW-Extension Cooperative Extension. And on behalf of those folks and our other co-organizers, Wisconsin Public Television, Wisconsin Alumni Association, and UW-Madison and Science Alliance, thanks again for coming to Wednesday Nite @ the Lab.

We do this every Wednesday night, 50 times a year. Tonight it's my pleasure to introduce to you, Paul Block. He's a professor here in the Civil and Environmental Engineering Department. He'll be talking to us about the Grand Ethiopian Renaissance Dam.

And for a state that in its constitution says that the waters of Wisconsin shall remain forever free, it's a big deal to talk about dams and what they do to communities, to countries and to international relations. Paul was born in Winfield, Kansas, grew up in Seward, Nebraska, went to undergraduate at Valparaiso University in Indiana, then spent several years teaching in Europe and in Africa. And he spent several years in Minnesota at Rochester, then got his PhD at the University of Colorado in Boulder, then post-doc-ed at Columbia University, went on to Drexel University in Philadelphia. And then three years ago, he came here for an interview in January.

(audience laughing) And we thought we were putting him through something and then somebody said, "Oh yeah, he's lived four years "in Minnesota," Hmmm. So I'm delighted to have Paul here tonight to talk about the Grand Ethiopian Renaissance Dam in Africa, thank you. Thank you very much, Tom. (audience applause) Thank you, I appreciate that.

Thank you very much for coming this evening. It's a really nice chance and opportunity to be able to present some of the research activities that are happening in my research group. And I should very much state clearly up front that my students and post-docs have done most of this work. So if this is an enjoyable presentation for you, we can give them the credit.

If it falls flat on its knees, then we can blame me for that. So I'm in Civil and Environmental Engineering. I think mostly about water resources management. Much of my work is internationally focused.

Some of that work is in Ethiopia. Some of that work is in South America as well, although, I do have some students that are focusing on projects here in Wisconsin, even as close as Lake Mendota. Some students that are focusing in Texas as well. And then others that are focused on a more global approach.

So I want to emphasize the fact that I'm an engineer. And although I'm going to be talking broadly about Ethiopia and about the Nile and the Nile River basin, I'm not going to inundate you tonight with facts and figures about hydropower generation. So if you came to hear that, I'm sorry to disappoint you. But I'm also not a historian, and I'm not an expert on Ethiopia.

But what I'd like to do to start out is provide a little context. So how is it that Ethiopia came to be in the state that it is in now? The decisions that are being made by Ethiopians and Ethiopian government, the context of Ethiopia within the Nile basin, what has lead up to that? And again, this could be an hours-long presentation, and I will have one slide or so on that.

But let's begin with that. I think many of us, when we think about Ethiopia, we think about this. We think about starvation, we think about famine. And I think this really came into play from this 1984 drought, very severe drought and famine in Ethiopia.

And not only that, it was one of the first times that pictures were taken such as this, of these dire conditions and broadcast on American televisions. And that, in many ways, set the tone for how many of us do think about Ethiopia. And this is not inappropriate, because there is poverty in Ethiopia. And there is struggle and there is hardship.

But Ethiopia is a diverse place, and it has many other aspects to it much beyond this. This is Ethiopia. It's very green in many places, and these crops look quite lush. I think this is maybe sorghum or something like that in the front.

In the back, it's a green grass that looks a lot like a wheat and they call that teff, and this is the main grain that they use in their bread, injera. So so you will find teff planted many places in Ethiopia. Ethiopia is a mountainous country, also. Some very high mountains.

People don't oftentimes think about that. It can be very rocky, which makes agricultural practices difficult. Many places are de-forested, like this one has been. So the trees are much more sparse.

Other places, there are these old-growth forests that haven't been destroyed. Although, estimates say about 97 percent of Ethiopia has been de-forested. So it's a very important part of their ecological condition. There are modern cities in Ethiopia.

This the capital, Addis-Ababa. It sits at about 8,000 feet elevation. In a trip there I took there this summer, I had a colleague or friend who said, "Well, I hope it's not too hot for you in Africa," as I left Madison, where it was maybe 90 degrees. It was 72 degrees there, right?

And it was the rainy season. So it was cool, and it was actually very damp. But lots of construction happening. Lots of people that look quite modern.

And we can contract that with some of the rural areas, which are much, much different, and people living in very different kinds of homes or dwellings. Also in the rural areas, it's not uncommon to find something like this, where you have people and you have livestock sharing the same resource, right, for drinking, for cleaning clothes, animals defecating in this. And this has caused some real, real problems in terms of disease with people. Well, in animals, as far as that goes.

And then you have a mix of the two at times, right? So this is a modern city in Ethiopia, beautiful building in the background, a brand-new building, Bahir Dar University. And in the front we have a herd of cattle, or not cattle, a herd of goats moving through. So it's not uncommon to be walking down the street, on your feet or on a bike or in the car, and have to stop suddenly for some livestock to pass through.

And that's common every day. It doesn't come as a surprise to anyone living in Ethiopia. And contrast that with other parts of Ethiopia that look like this, desert and flat. And this is a salt caravan.

Still very common to see these in certain parts of Ethiopia, moving across the landscape, transporting salt. So a few figures now just to, again, set the context for Ethiopia. This is topography. So this is Ethiopia.

These are mountains on either side, and then the rift valley runs through the center of Ethiopia. So we have some very low elevations, some deserts and hot areas here, but some high mountains in these regions as well. Here's a zoomed-in part of the rift valley at the Awash Valley, and it's a endorheic basin which means its one of the few major basins in the world where there's no outlet for its lakes and streams. So the water essentially flows in but then has no outlet.

It never actually reaches the sea. In terms of land cover, you can see that the western and the eastern side of Ethiopia are quite different. It's much more green and, again, it was mountainous on the western side. The eastern side, much more flat, dry and desert.

The dark green here are old growth forests. You can see that there are not as many left in the highlands as there were historically. Then just thinking a little bit about precipitation and temperature, what are some of the meteorological conditions like in Ethiopia? And again, they are very diverse as well.

So in the western side, the darker blue colors means more precipitation. And on an annual average, you can see that some places are getting upwards of two meters of precipitation every year. That's a lot, that's a lot of precipitations. More than we get on average here in Wisconsin.

Other places hardly get any, only a few inches. So as you might guess, the western half is more of the breadbasket of Ethiopia. It's where most of the agricultural lands are. 85 percent of all people in Ethiopia are farmers.

This is a huge part of their economic situation, and part of their GDP is the agricultural sector. So 85 percent of Ethiopians are farmers, and about 99 percent of those are rain-fed farmers, meaning there's very, very little irrigation. I'm not showing it here, but the year-to-year amount of precipitation can vary a lot. So in some years, they get sufficient amounts of precipitation to grow their crops.

In other years, there's insufficient amounts. And so what happens in those circumstances, it becomes very important. Many of these farmers are subsistence farmers, meaning they're growing just enough food for them to live on. And so after the season, they harvest and they store some of that food and eat that throughout the remainder of the year.

And then they have what they call the lean season, where, while they're planting their crops and waiting for the harvest, they're hoping that their stores from the past year have not run out. There are lots of different programs. Since the 1984 drought, many NGOs have set-up in Africa, especially in Ethiopia and provided work, labor for food-type programs, where if there is a failure of the rains, many of these farmers do go into the cities and other places and labor and are able to earn some income that way. But it's a real, a real concern in Ethiopia.

Temperature, on the right, kind of goes along with the precipitation. Speaking of food security or food insecurity, there is this organization called the Famine Early Warning Center, or system. And they have a network where they're continually doing monitoring of the crop situation, what do yields look like, et cetera, during the growing season, to try to have a good head's up if possible about where some of the points of concern or places of concern might be so that we don't encounter conditions again like 1984. And a big challenge with something like 1984 was everything was very re-active, right?

So the idea here is to try to be a little bit more pro-active, although it's not simple; it's still complex. What's happened historically in places like this? Well, for example, if there's a famine or insufficient amount of food in Ethiopia or other African places, historically, grain from the West, from Europe, from the United States has been freely given to people in that country. And that's a wonderful gesture, right?

And it's important for those people that are impoverished or starving. But maybe all of those people happen to be in this part of Ethiopia, and the farmers that are up here are actually having a relatively normal year from a climate perspective, and they're able to grow a crop. Well now, with all this free food flowing into the country, their crop is really of no value, they can't sell it. They can eat it themselves, but they can't sell it, right?

So in some situations, they're not a whole lot better off than their compatriots in another part of the country. So these things are very complex. I'm an engineer, right, so I don't have any of these economic answers. But we do know that the situation is very complex.

So these type of tools that are monitoring the situations are quite important. So what about some of the infrastructure in Ethiopia? Here I'm thinking specifically about storage and water storage. So reservoirs and those types of things.

And there's a pretty strong correlation between the amount of storage that you have in your country and your economic well-being. So here on the right, we have how many cubic meters of storage are available per capita. In the United States, we have a very high number. So we have a lot of storage.

We have many reservoirs. Those might be used for energy production. They might be used for irrigation for agriculture, for other reasons as well, right? But you can see some of these top countries are some of the countries with the larger economic or GDPs.

In Ethiopia, on this graph, happens to be way down here. So that's the context, that's part of the situation. A low amount of storage per capital. Ethiopia is about 90 million people right now, just to put that into context.

Water storage can be good, because it can buffer this variability. If you irrigate your crop and you have a reservoir, in some sense, maybe this sounds crass, but you don't care how much it rains or doesn't rain, because you're just going to irrigate the difference, anyway right? So you buffer that variability. It's a little bit like insurance, but it's expensive and it's controversial, right?

Well, that is very much changing the riparian situation if you're storing the water. It's changing the ecology. It's fish habitat that might no longer be able to... be the same as it was before.

So what about energy comparisons for sub-Saharan African? How do these compare for some of the different countries in sub-Saharan African? I'm sorry, you probably can't read these, but there are a number of countries up here, Ghana, Cote D'Ivoire, Cameroon, that have a fair amount of energy production. This is megawatts per million people.

So just to give you a bit of context, our Hoover Dam in the United States is rated at about 2,000 megawatts. That's how much power it has in terms of capacity. So many of these countries are doing better than Ethiopia. Ethiopia is down here.

And this is a little bit of an older statistic, so I tried to extend that line to show where they are now. And they're doing a little bit better in terms of energy production. And when they bring online the hydro-power facility that I'm going to present on and speak mostly about tonight, this is how that will change. So it's going to change things drastically...

in comparison to other sub-Saharan countries. It's going to be an important piece of not just Ethiopia's infrastructure, but the regional infrastructure and arguably, the African infrastructure as well. So what about Ethiopia's energy needs? Here's a graphic from the World Water Assessment Programme in which they're classifying different countries in terms of global physical water scarcity or economic water scarcity.

So if you have physical water scarcity, it simply means that you don't have enough. Your demands are out-pacing your supplies. On the other hand, if you have economic water scarcity, that means that you don't have sufficient infrastructure in place to be able to take advantage of the water resources that you do have. And that's where Ethiopia falls.

Ethiopia falls into that economic water scarcity category. And as you can see, much of sub-Saharan Africa does as well, which maybe doesn't come as a large surprise. Climate change may change this eventually, but there is still a lot that needs to be done in terms of infrastructure development, that point aside. So what about some of Ethiopia's energy needs or capabilities?

They have a wealth of hydropower potential, about 30,000 megawatts. Remember, I said Hoover Dam was about 2,000 megawatts. So they have about 15 Hoover Dams worth of potential hydropower. That's a lot.

And that's the economically-feasible hydropower. They could actually develop more, it just may not pay itself back. There's only one country, actually, in Africa, the Democratic Republic of Congo, that has more hydropower potential. So Ethiopia-- Of course.

So Ethiopia sees this as its oil, if you will. They see this as their mechanism to spur their economy. And they have goals and ambitions of being a mid-level economy by some time in the 2020s. And they're attaching their wagon to...

They're hitching their wagon to hydropower as a way to do that. So as of the present, they have less than 10 percent of that hydropower developed. The context within Ethiopia is about 80-some percent of Ethiopians still lack access to electricity. There are some studies that talk about correlations of education and literacy to access to electricity.

So that's a very positive development that has externalities beyond just turning on a light bulb and being able to see where you are. And many, many people within Ethiopia are still relying on wood and biomass for their cooking fuels, where that may transition if they have access to electricity. Okay, still setting the context, I promise I'll get to some of the other, more technical details. So with that, I'm going to move out a little bit from Ethiopia and talk a little bit about the Nile River, the Nile basin and how Ethiopia fits into the context there.

So the Nile River is formed by two main rivers. The first one, here's Ethiopia, is the Blue Nile River, and it starts at this lake here called Lake Tana. So this is at fairly high elevation, and it flows through these, through the Ethiopia highlands through a fairly stark, steep channel out of Ethiopia and into Sudan. And the other half of the Nile River is the White Nile River, and it starts farther south, generally at Lake Victoria, although there are some tributaries to Lake Victoria.

That travels north through Uganda and then through the swamps of Sudan where it slows down considerably and has large lateral flow and extent. And then continues on to Khartoum in Sudan, where it meets the Blue Nile, and then it forms the main Nile through Sudan, through Egypt and out into the Mediterranean Sea. So just a few statistics,

then

it's about 6,700 kilometers long, and there are ten countries that fall within the basin, including South Sudan now as well. Why the Blue Nile and the White Nile? I think they were probably aptly named. The Blue Nile maybe should be the Brown or Black Nile.

So in the summertime, their summertime is the same as ours, is when they get the majority of their precipitation, and that's when the river rises to its peak. And I think you can see this, but it carries a lot of, a lot of sediment with it. So it becomes very brown, very heavy with this sediment. Whereas, the White Nile carries very little sediment.

And if you recall, I said it goes through these swamps where, if there is some sediment, a lot of that settles out. So I probably should have put a picture, but if you look at a photo, an aerial photo of where the two rivers come together, you can clearly see which one is the Blue Nile and which one is the White Nile. They look starkly different due to the sediment load. So again, the Nile River, a very long and rich history.

We could spend hours talking about this. Egypt is the gift of the Nile, and there's a lot of founding civilizations. Civilizations, I should say, were found along the Nile River and depended on it. Very much even so today, alright?

A lot of religious connotations with the Nile, long historical, you know, searches for the sources of the Nile that carried on for centuries and centuries. And then colonialism, we have to remember, is a part of this story as well. So all of the countries, minus one, that are in the space were colonized at some point. The country that was not was Ethiopia.

And they're actually very, very proud of this, if you talk to them. Their sovereignty is something that, that they hold up. They were occupied during the Second World War for maybe four years or so by the Italians, but they were never colonized. If you go to Ethiopia now, sometimes you can see some storefront that doesn't look like anything reputable on the outside and you go inside, and maybe still there's nothing really to attract your attention, but one of the chief outputs, agricultural outputs of Ethiopia is coffee, so coffee beans.

And then I don't know if this is completely true or not, but then you had this Italian influence, right? So you go into one of these shops and you see this beautiful stainless-steel Italian espresso maker, bring in the Ethiopian coffee beans, and you have a wonderful beverage there. So I don't know that Ethiopians were excited about this, this period in their history, but they do make good coffee, that's for sure. Okay, so my only slide on the background there.

What I'd really like to focus a little bit more on is the Nile River allocations. How is the water used or parsed out between these countries? And this forms a huge topic in the literature on hydro-politics. So hydro-politics, across many, many different disciplines.

So speeding up and skipping a lot of different things, there's this very important agreement of 1959, or Treaty of 1959, where the waters of the Nile were allocated to Egypt and to Sudan. And this was still under a period of colonialism for Sudan. So Egypt negotiated this with Sudan, who was a British colony, right? And Egypt, a former British colony, so there's a little bit of that history as well, okay?

But the water essentially is allocated between these two countries. And so this agreement, according to the countries of the basin, was only agreed upon, or signed-off on, by the Sudanese and by the Egyptians themselves. So what this says is, all the water coming from these rivers shall be kept in the river, and Sudan will have access to 25 percent of that flow and Egypt will have access to 75 percent of that flow, which essentially has left the upstream countries with zero rights, or zero allocation by name. Now that doesn't mean that they couldn't, the upstream countries could do no development, and they have done some development, but it's been limited.

It's been limited. And of course, Egypt has been the strongest country in terms of economy in the region, and so that has played into this as well. Well, if we fast-forward then to just a few years ago, there's this Entebbe Agreement, where the other upstream countries, minus about one or two of them, have signed on to this to say, "We officially call this 1959 treaty invalid. "We are not going to abide by this.

"We don't believe that we were ever party to that." And so that's the context right now. As you can believe, Sudan and Egypt have not signed on to that, right? And it's probably not in their best interest to do that. I don't know that I would either if I were in their shoes.

So without trying to lay any judgment, that is the context and that is the situation. But what does Ethiopia actually contribute to the Blue Nile? What do they contribute to what goes to Egypt? So here's the Blue Nile and here's the border with Egypt and Sudan.

And about 45 billion cubic meters per year on average passes that point, okay? And this turns out to be about, there are other tributaries, and of course the White Nile, but this turns out to be about 60 percent of the total flow that makes it to the High Aswan Dam. Okay, so about 60 percent of that comes from the Blue Nile from Ethiopia. Well, Ethiopia also has some other tributaries, both north and south of the Blue Nile that are part of the Nile Basin.

And it turns out, overall, Ethiopia contributes about 85 percent of the total flow that makes it to Egypt. Again, just setting the context. Okay, is that a point for contention or tension? Probably so, right?

Probably so. Is it unique in the world? No, right? There are many, many different international basins.

As a matter of fact, there are 260 different international basins globally. And about 40 percent of the world's population live in those basins. A decade and a half ago, Kofi Annan, I'm sure most of you know, said that, "Fierce competition for fresh water "may well become a source of conflict and even wars "in the future." And that very well is and could be true. However, to date, there really are no wars, according to a research scholar, a professor, Aaron Wolf, at Oregon State University, over water.

There are no wars that have been fought over water. But there are some notable exceptions. And when I say notable exceptions, sometimes where, perhaps, we've gotten close, right? But things haven't escalated to that level.

Just a few of them,

quickly

some of you may be familiar with the Picnic Talks in Israel, between Israel and Jordan, where there was a contentious period, I want to say in the 1950s or '60s, about allocations of the Jordan River itself. And they actually worked out an agreement informally... to alleviate some of these tensions, and the escalation before anything, long before anything formally was decided. The Mekong River, there's the Mekong River Basin Commission, I believe it's called, and that has contracts and compacts between the countries.

And this compact continued to function throughout the Vietnam War, even though those countries, I guess one could say, were bitter enemies at the time. And then the last example, which I appreciate... thinking about India and Pakistan, there's the Indus River which flows from India to Pakistan, and they have a compact that is set up that India must let so much water pass per month or per year. And this was in place in the 1950s and '60s when they had many conflicts.

It was during one of those conflicts that India failed on its part to pass a certain amount of water to Pakistan. But even though there was this conflict or this war that was happening between these two countries, India paid its fine to Pakistan for that happening. So the big context here is, I think there's some appreciation for water internationally. And there's some appreciation for...

the international trans-boundary rivers and the compacts that have been set up. But at some point, this may not hold, right? At some point, we may see conflict. Let's hope that's not in the Nile Basin.

So back to the Nile Basin. So this is the situation. In 2011, Ethiopia announced, literally announced to the world, that Project X was underway. And what this turns out to be is this is the Grand Ethiopian Renaissance Dam.

And they had started construction, and it really came as a surprise to everyone. It was maybe one of the best-kept secrets, at least regionally. What else was happening? Well, coincidentally maybe, if you say, what happened or was announced during the Arab spring time.

So Egypt was, perhaps, in a bit more situation of turmoil. So maybe it was opportunistic. I can't say for sure. But it is the first dam in Ethiopia that is being constructed right on the main stem of the Blue Nile.

So Ethiopia does have some other much, much smaller facilities that are built on these tributaries. But this is truly important, because it's the first one that will actually block the river on this main stem of the Blue Nile. So as you can imagine, this got attention of downstream countries. And the downstream countries that we now are going to be talking about are Sudan and Egypt.

And those are the two countries that are downstream of Ethiopia that utilize these waters from the Blue Nile. So there have been on-again, off-again discussions and talks by this tripartite committee, which constitutes these three countries. And I will say it's been anywhere from handshakes and agreement on parts to military threats. There's the famous story of, maybe a couple years ago, where there was a high-level diplomatic-- just a high-level government meeting of Egyptians, and they didn't realize they were being mic-ed and on television, and one of these high-ranking officials said, "Well, if they don't stop construction, "we may just have to take military action "and fly in there and bomb it." And of course, that got lots of attention, right, once that got out.

So it's gone from that to all the way to now where we hope we're in much more of an agreeable, amicable situation. And there's some ways forward. So we'll talk a little bit about what some of those issues are. So very quickly, what are some of the advantages and disadvantages of large-scale storage, in general?

Well, storage can provide flood protection, hydropower generation, regularization of flow. So instead of this big flood wave that comes in the summer, more even flows throughout the year, a reliable supply, recreation, navigation, many of these things. Well, what are some of the drawbacks? These are generalities, right, for all storage, large-scale storage.

You're inundating now. The reservoir is inundating a large swath of land. You may be relocating people, trapping lots of sediment behind this reservoir, changing the flows of the river, the ecology of the river. And then if it fails, of course, that is of huge concern to the inhabitants downstream.

Okay, so finally, half an hour into the presentation, we get to the Renaissance Dam itself. And this is a schematic of what the Renaissance Dam is to look like, and then this blue outline is the expected reservoir boundaries. And it's been under construction, as I said, since about 2011, and is expected to finish in probably 2018 as of now. The chief engineer, as of now, says that they are about 45 percent of the way completed with construction.

It's going to have a large generating capacity, about 6,000 megawatts. So again, for my comparison with the Hoover Dam, that's about three Hoover Dams. It will be the largest dam in Africa, in terms of size and in terms of generating capacity. Its reservoir size is enormous, we'll say that, it's enormous.

And it's going to be very expensive. Now so far, Ethiopia has decided to self-finance this themselves. So they are asking for bonds from their people and from the ex-pats that live, you know, in the U.S. and in other places to help fund this.

There's a great sense of pride in Ethiopia about this. Government employees are asked to give one month of their salary towards this project, and we certainly hope that it can continue to be financed. But that's a real question, right? Can it be financed the whole way through?

So just a couple pictures you might be able to see, or not so well. So you can see this in Google Earth quite well. So this is a Google Earth zoomed-in picture. And this is the dam itself.

Okay, so you can see the river still continues to flow through, and they're building on both sides. From this point, this will be one abutment. All the way over here will be about another abutment. That's about a mile, okay?

So it's a very, very long dam. I'll show you some more pictures. But this is the dam. Well, what else happens on a dam construction site?

This is the blasting area, and they built a whole cement factory, of course, enormous amounts of cement that go into this. And this is the community, right, that's been built. About 9,000 people are working on the dam at any given time. Here's the cement factory, and just to show you the scale of what has to happen for such a large infrastructure project to take place.

We zoom in a little bit. Again, this is the dam here. The water will flow through both sides, here it will divert. So eventually, this will be blocked off.

This will be the final piece of construction, and water will be diverted through both sides. And one power house will be on this side, and another power house will be on that side. Here's a picture just to start to give scale a little bit of one side of that facility. I had to show one picture of myself there.

You probably can't see it, but I actually have my eyes closed, it was a very bright day but this down here, if you can see that, is one of those enormous trucks. It's not a typical-size dump truck, it's an enormous truck that you might find at a mine or something like that. So this is just to give you an idea of scale. And they're about, again, 50 percent of the way, so they're going to be all the way up here by the time that they're done.

I'm going to try to play this just very briefly, if I can. Okay, maybe it won't play, which is fine. But this is looking upstream, and then it just panned across to show you what downstream looked like as well. But even though this is looking upstream, it's a similar scene looking downstream.

And there are mountains at about this point downstream, and those mountains are in Sudan. So we're talking about, on the order of 15 to 20 kilometers from the Sudanese border. So this dam is right on the border with Ethiopia and Sudan. One more picture here.

Again, here's the dam zoomed out. And over here, we have a second dam that's being built. It's called a saddle dam. And this is five kilometers or about three miles long.

Just piles and piles of rock, and it'll have a concrete face on it. And the reason for this is so that they, this is the low spot in the area. So they can raise it, and it allows them to get a lot more volume in their reservoir. I also don't know if you can see this, but you can see that there's a slightly different color between here and here.

So this area is still treed. All of this has been de-forested. And so this line between the two different shades of grey is where essentially the boundaries of the reservoir will be, or the shoreline. So they've deforested and collected all these trees.

One, so they can use them, but also, so that there's a reduction in the amount in methane that's released once inundation starts. Okay, so what does this all mean for downstream countries? What do Sudan and Egypt think about this? Is there an agreeable way forward, or not?

So some of the benefits and costs to Ethiopia, they're very interested, obviously in generating hydropower for themselves. But they are also going to have to export much of that to the neighboring countries. Presumably, this will be a humanitarian boost to Ethiopia, as well, but the financing is a real question mark, okay? So $5 billion is a lot of money.

Some of the benefits and costs to Sudan. Well, there will be this idea of regulated or more even stream flow which is a good thing, in some ways, for their hydropower. They might be able to irrigate a second cropping season in some places, and Sudan is very interested in doing that. And it provides some flood control as well.

It's going to be a silt trap and it's going to hold back a lot of the sediment. That's good and that's bad. It's good in terms of the hydropower facilities downstream in Sudan, now won't have to deal with this problem. They have a lot less sediment.

But there's a historical practice of flood recession agriculture, where this flood wave comes down and lays out these nutrients on the banks of the river, right? And the floodwaters recede, and farmers come down and plant on this nutrient-rich soil, get wonderful harvests and then they move back up and the cycle repeats itself. That practice will completely go away. The reservoir here is a much higher elevation at the reservoir, say, behind some of Egypt's facilities, specifically the High Aswan Dam, which is in the middle of the desert.

And so the evaporative losses are going to be quite different between those two. There might be cheap electricity available to downstream countries, but they also may be subject to less control of the river. So one piece in particular that some of my students, one who is here, has been focusing on is, Well, not only how do we operate this thing in the long-run, but how do we fill this reservoir up? Not physically how do we fill it, we know how to do that, but how do we fill it?

Ethiopia has sunk lots of money into building this dam. And just by pure economics, they would like to fill this up more quickly so that they can start generating electricity, sooner than later. If they wait 20 years from now, economics say they're not going to be able to get as much return on their investment, right? Downstream countries probably are not in favor of Ethiopia filling it up so quickly, right?

Their lives and livelihoods are dependent upon these waters. So what's an agreeable way forward? And so we looked at three different things here, okay. Ethiopia is interested in hydropower generation.

Sudan, somewhat, but they're really interested in irrigation water. And Egypt is really interested in in-flow to Lake Nassir, which is behind their High Aswan Dam, which is their main storage facility for hydropower and for irrigation downstream as well. So how do some of these different... How would different options for filling the reservoir play out for these three different countries?

Maybe I'm giving this away a little bit, but it turns out now that Sudan, that's the first country downstream is very much in favor of this dam. They see a lot of benefits coming from this. So they essentially are on-board with Ethiopia building this dam. Egypt, on the other hand, still has some challenges with this construction going forward.

So again, this is the area, the basin that drains to the Ethiopian Renaissance Dam. And this is generally what the precipitation looks like, if you say January through December. So most of the precipitation in their summertime. And this big flood wave that also comes in late summer as well.

This is maybe not an intuitive figure, but what this is is streamflow at that point every year. And so what I want to point out here is, we have some periods of very high stream flow and some periods of very low stream flow. So I'm not going to get into too much here in this presentation, but when they close the gates and start filling the reservoir, it's a very, very different situation if we get some years like this than if we get some years like this, all right? It's a very different situation.

Okay, so just real quickly for those of you that might not be hydropower buffs, what are we interested in? Well, to generate power, we need two things. We need to have head, and that's this difference behind the level in your reservoir, behind the level of the surface water in the reservoir and the level downstream. So you want to get that as high as you can.

And flow, how much water can you get through your pipes to generate electricity? So those are the two things that we're most concerned with. So we have a system of models that we use. We take a hydrology model and put that through a reservoir model.

It's a decision-making model. So this is the Renaissance Dam model. And then how does that play out downstream? So modeling that as well.

So just one slide on our hydrology model. We take many of these meteorological conditions and we're able to say, "Okay. What is stream flow, then, "coming into the reservoir behind the Renaissance Dam?" Jumping over to the Water Balance Model, this is the Renaissance Dam itself. But then we have also these other, the White Nile and other contributions as well, so that we can see what does that mean for stream flow at different points along our system.

And then thinking a little bit about some of these reservoir-filling policies. We can come up with many, many different policies. We've looked at two different varieties. There are two different varieties that I'm going to present here.

One is that Ethiopia could simply decide to impound a certain fraction of water that passes by every month or every year. So they could say, "Well, we'll take five percent "or 10 percent or 25 percent of the water that passes. "We'll keep that amount. "The difference will be passed downstream." That's one type of policy.

Another type of policy could be such that, well, what if we take the long-term, historical average, so what on average passes? And if there was more water than that, Ethiopia or that amount can be impounded behind the Renaissance Dam? If it's less than that, we have to pass all of it. So what does that look like?

Well, in a year like this, where you get lots of water, and here's the historical average, Ethiopia would get to keep that much water, whatever that amount is, okay? If it's less, they could impound none. So looking at a few of these. One thing that people might be interested in then, is, well, how long does it actually take to fill this reservoir?

Are we talking two years, fifty years? And under some of these different filling polices, we've run out some of these scenarios where this is months. And it turns out in some of the policies where you're impounding more water, it takes about six or seven years, on average, to fill the reservoir. Now remember, and I'm emphasizing "on average", if there are a few successive dry years, it may take longer.

If there are some successive very wet years, it could take less time. It turns out that if you only filled it at about five percent each month, I don't think it would ever fill up, right? And that's because we have some losses just due to evaporation as well. So that's probably a policy that's not going to be selected.

So on average, it's about six years after filling has started in earnest. And so then we can start to think about what does this mean for Ethiopia? So we can look at some of the different policies and how much hydropower is generated. And no surprise, for some of the policies where we're able to impound more quickly, the Renaissance Dam is able to generate hydropower more quickly.

And we can start to think about what this means in terms of downstream flows as well. So the black line here is historical flows. Each of these different policies has more or has less downstream flow, but to what extent? Sudan and Egypt are going to be very interested in this for their planning purposes.

Maybe not the best kind of graphic to show, but what I'd like to say here is, we looked at two different locations. One in Sudan, where there's this extremely large crop-irrigation scheme. And what would it look like in terms of reductions there of water, depending on how much we reduced it at the Renaissance Dam? So remember, a 10 percent reduction at the Renaissance Dam doesn't mean 10 percent in Sudan, because there are other tributaries along the way.

So in general, a 10 percent reduction there means about an eight percent reduction, or something like that. What about this 25 percent filling policy? Maybe it means 22 percent reduction. But at some point, maybe after about six years, that tails off, right?

But there will always be some reduction due to evaporative losses from this reservoir. And what does that mean for Egypt downstream? Believe me, Egyptians are very, very interested in these types of numbers, right? So for a 25 percent flow policy during that filling stage, our calculation are saying that's about a 12 percent reduction.

So it's a very real number that Egyptians would like to re-operate or at least plan for. One figure only to say that climate change will come to bear on this, it's unclear how right now, but many of the models are projecting a general wetting in this part of the world, which will hopefully work in favor of those countries. And in the end we can say, "How much water does that mean "will reach Lake Nassir, in this case?" Okay, so just a couple of thoughts here. Some of the major remaining challenges.

Right now there is no agreement between these three countries on the filling policy. And we and many others see this as a real gap because this lack of planning, in the end, will probably harm all the countries to some extent, some maybe more than others if there's not this agreed-upon policy. So I think it's certainly in the interest of the countries to do this. There have been talks and negotiations, but as of yet, no formal policy.

And we are not that many years away from filling happening in earnest. Further analysis needs to be done on what some of the downstream impacts are, chiefly, of course, in Sudan and Egypt. What is this going to mean for those countries? There's no trans-boundary agreement.

We have these historical agreements. But with this new dam going in, we have a whole new hydroclimatic regime, or at least a whole new hydrology regime. And there's really no, no instance that I know of where you have or will have these two major, major assets, the Renaissance Dam in Ethiopia and the High Aswan Dam in Egypt that are uncoordinated, okay? That their actions and their operations are uncoordinated.

So there's very little evidence that I'm aware of and that could be a recipe for disaster. And then this idea of Ethiopia is going to generate a whole lot more hydropower than they're going to be able to absorb. I think there's no question about that, at least in the near term. So they're going to need to export a lot of this.

So that means a lot in terms of transmission, in terms of setting up these contracts, et cetera. So the bottom line is, there's a lot happening, but there's a lot more that needs to happen in terms of cooperation, I believe, to address some of these major challenges. And so with that, I will be happy to take any questions. But thank you for your attention, and I have some information there if you'd like to be in contact.

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